Passwords are no longer sufficient for protecting important logins. Two-factor authentication — something you know + something you have — is a practical, proven technique for preventing account takeover.

Duo Security offers two-factor authentication as a service for SSH, VPN, web apps, and more. The service takes only a few minutes to set up and supports a variety of authentication factors: mobile app, phone callback, SMS, and tokens such as YubiKey. The best part? If you’re using a smartphone, there are no codes to transcribe: just tap “Approve” to authenticate.